/*
 * NamespaceDecorator.java July 2008
 *
 * Copyright (C) 2008, Niall Gallagher <niallg@users.sf.net>
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
 * implied. See the License for the specific language governing
 * permissions and limitations under the License.
 */

package wx.xml.simpleframework.xml.core;

import java.util.ArrayList;
import java.util.List;

import wx.xml.simpleframework.xml.Namespace;
import wx.xml.simpleframework.xml.stream.NamespaceMap;
import wx.xml.simpleframework.xml.stream.OutputNode;

/**
 * The <code>NamespaceDecorator</code> object is used to decorate
 * any output node with namespaces. All namespaces added to this are
 * applied to nodes that require decoration. This can add namespaces
 * to the node as well as setting the primary namespace reference
 * for the node. This results in qualification for the node.
 *
 * @author Niall Gallagher
 * @see wx.xml.simpleframework.xml.core.Qualifier
 */
class NamespaceDecorator implements Decorator {

    /**
     * This is used to contain the namespaces used for scoping.
     */
    private List<Namespace> scope;

    /**
     * This is used to set the primary namespace reference used.
     */
    private Namespace primary;

    /**
     * Constructor for the <code>NamespaceDecorator</code> object. A
     * namespace decorator can be used for applying namespaces to a
     * specified node. It can add namespaces to set the scope of the
     * namespace reference to the node and it can also be used to set
     * the primary namespace reference used for the node.
     */
    public NamespaceDecorator() {
        this.scope = new ArrayList<Namespace>();
    }

    /**
     * This is used to set the primary namespace for nodes that will
     * be decorated by the namespace decorator. If no namespace is set
     * using this method then this decorator will leave the namespace
     * reference unchanged and only add namespaces for scoping.
     *
     * @param namespace this is the primary namespace to be set
     */
    public void set(Namespace namespace) {
        if (namespace != null) {
            add(namespace);
        }
        primary = namespace;
    }

    /**
     * This is used to add a namespace to the decorator so that it can
     * be added to decorated nodes. Namespaces that are added will be
     * set on the element so that child elements can reference the
     * namespace and will thus inherit the prefix from that elment.
     *
     * @param namespace this is the namespace to be added for scoping
     */
    public void add(Namespace namespace) {
        scope.add(namespace);
    }

    /**
     * This method is used to decorate the provided node. This node
     * can be either an XML element or an attribute. Decorations that
     * can be applied to the node by invoking this method include
     * things like comments and namespaces.
     *
     * @param node this is the node that is to be decorated by this
     */
    public void decorate(OutputNode node) {
        decorate(node, null);
    }

    /**
     * This method is used to decorate the provided node. This node
     * can be either an XML element or an attribute. Decorations that
     * can be applied to the node by invoking this method include
     * things like namespaces and namespace lists. This can also be
     * given another <code>Decorator</code> which is applied before
     * this decorator, any common data can then be overwritten.
     *
     * @param node      this is the node that is to be decorated by this
     * @param decorator this is a secondary decorator to be applied
     */
    public void decorate(OutputNode node, Decorator decorator) {
        if (decorator != null) {
            decorator.decorate(node);
        }
        scope(node);
        namespace(node);
    }

    /**
     * This is use to apply for <code>NamespaceList</code> annotations
     * on the node. If there is no namespace list then this will return
     * and the node will be left unchanged. If however the namespace
     * list is not empty the the namespaces are added.
     *
     * @param node this is the node to apply the namespace list to
     */
    private void scope(OutputNode node) {
        NamespaceMap map = node.getNamespaces();

        for (Namespace next : scope) {
            String reference = next.reference();
            String prefix    = next.prefix();

            map.setReference(reference, prefix);
        }
    }

    /**
     * This is use to apply the <code>Namespace</code> annotations on
     * the node. If there is no namespace then this will return and
     * the node will be left unchanged. If however the namespace is
     * not null then the reference is applied to the specified node.
     *
     * @param node this is the node to apply the namespace to
     */
    private void namespace(OutputNode node) {
        if (primary != null) {
            String reference = primary.reference();

            node.setReference(reference);
        }
    }
}
